This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | -10 |
| 4 | 111 |
| 5 | -1231 |
| 6 | 13652 |
| 7 | -151403 |
| 8 | 1679085 |
| 9 | -18621338 |
| 10 | 206513803 |
| 11 | -2290273171 |
| 12 | 25399518684 |
| 13 | -281684978695 |
| 14 | 3123934284329 |
| 15 | -34644962106314 |
| 16 | 384218517453783 |
| 17 | -4261048654097927 |
| 18 | 47255753712530980 |
| 19 | -524074339491938707 |
| 20 | 5812073488123856757 |
| 21 | -64456882708854363034 |